The present invention pertains to a strap dispenser. More particularly, the present invention pertains to a strap dispenser for use with a strapping machine that assists starting movement of the strap coil upon tensioning of the strap as it is pulled from the coil.
Coil dispensers are used as a source or supply of coil material for many operations. In one application, strapping material is supplied on a coil for use in a strapping machine. Various types of strapping machines are known in the art and will be recognized by those skilled in the art.
The strapping material is fed from the coil to the strapping machine. The coil is supported on a coil dispenser that provides a controlled source of the strapping material to the strapping machine. The dispenser must permit feeding the strapping material to the strapping machine when there is a demand (e.g., as-needed) with little resistance on the material. The dispenser must also, however, prevent the coil from free-rolling (free rotation) so that the strapping material does not continue to feed from the coil when there is no demand for strapping material. To this end, the dispenser must include provisions to slow or brake the coil from free rotation upon a drop in demand.
It will also be recognized that the dispenser coils, particularly when the coil is full, can be quite heavy. As such, a fairly significant force is needed to commence movement (rotation) of the coil, even though the coil is mounted to the dispenser using a low friction roller bearing. This in turn requires that the strapping machine be able to develop a tension in the feed system in order to commence coil rotation.
One known dispenser includes a shaft about which the coil is mounted for rotation. A dancer arm pivots about the coil shaft and a roller is positioned at an end of the dancer arm opposing the arm axis of rotation. A brake assembly is mounted to the dancer arm for movement into and out of engagement with the side plate. The dancer arm is biased such that the brake is in engagement with the side plate. Other known dispensers use an electric brake that is mounted to dispenser at about the shaft to slow or stop that coil upon receipt of a signal from the strapper. None of these known dispensers, however, include any arrangement or provision for starting the coil from a stop. Rather, these are all concerned with stopping the coil to prevent free-rolling or overfeeding.
It is believed that dispensers were configured that use a pneumatic arrangement to assist or to help “push” the coil to start the coil rolling. However, it is not known whether these were successful in use or whether continued use of such coil start devices has been made. Moreover, because of the external assist (i.e., the pneumatic systems), these devices were complex and could require maintenance and attention beyond the value of their commercial use.
Accordingly, there exists a need for a coil dispenser for dispensing strapping material from a coil. Preferably, such a dispenser includes a simple brake mechanism, in conjunction with a start-assist or auto-start mechanism. Desirably, such a dispenser is of a simple design. Most desirably, the start-assist uses mechanical energy and the tensioning of the strap to actuate the start-assist.